The one thing that irritates me about batteries/battery holders are the ones that rattle around loose inside the case. For battery holders (Radio Shack or better) wired in, this is just tacky. If you are using terminals on the PC board, loose batteries can lead to poor connections. In either case, some attention to battery compartment design is necessary (and will cost you). I'd stick with the battery holders hardwired to the system with pigtails. Securing the battery holder is only a case of aesthetics.
Please don't use battery holders with those 9v (PP3) type clips. Unless you have a 6 cell AA or AAA holder (that puts out 9 volts), I've seen too many people loose the holder and then try to run the gizmo with a 9v battery (because it fits).
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Paul Hovnanian mailto:Paul@Hovnanian.com
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We are confronted with insurmountable opportunities.
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I'm working on a little battery powered gizmo for a customer, in a low-volume application. We're planning on using a few 'AA' cells, to be user-replaceable items.
What's your favorite way to mount batteries in products? I'd like something that's robust, dependable, doesn't present too many problems in manufacturing, and looks professional when the user opens up the case.
For all of the above reasons, a battery holder from Rat Shack is straight out.
So what do you like? Are there decent battery holders out there (Keystone)? Do the "clips on a circuit board" style work well for AA batteries? Have you used cases with built-in battery holders, can you get them that'll hold AA cells, and do you like them? Is your answer "none of the above", and if so what do you do?
TIA
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Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
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I know you are looking for quality products and my response isn't directed at that in particular, but you reminded me about the Microsoft "Instaload" bidirectional battery holder. What ever happened to that thing? Anyone using it? If so, which and from whom?
Tim, I have used several enclosures that have built in battery holders. You didn't say what size a product you have. I like the Serpac M series, which I am using for the Rainbow Color Reader. I also looked at several cases from New Age (available through Mouser) that had decent ergonomics. it depends on exactly what you are needing.
We had tremendous problems with battery contacts, even Keystone ones, in a range of industrial instruments. The problem was the lifetime of the units - a half life of about 2 years before the users managed to destroy them - and the rugged usage environment (not quite as bad as military, but plenty of knocks and drops). Despite rubberising the outside of the mouldings etc, the clips all eventually lost their springiness and it was a big reliability issue. A typical problem would be a power interruption for a few milliseconds when dropped, resulting in a power-on reset. For this reason I always preferred the rechargeable versions of the instruments where the batteries could have tags spot welded to them and we soldered them into boards.
If you decide to make your own contacts, there are many metallurgical aspects to consider such as plating the contacts with nickel, to prevent corrosion - all batteries seem to have a nickel plating - and making sure the rolled metal you stamp out is cut in such a way that it bends along the "grain" of the rolled sheet so it springs back rather than permanently deforming.
The most robust battery carrier we came up with for disposable AA's was one where the batteries were crammed in really tightly at each end. (We even tried a fancy one where the battery could move slightly and the contacts were held tightly around it, so there was a sort of internal rubbery cassette. Fail.) However AA cells vary quite a bit in dimensions, say 0.5 to 1mm, which is significant when you pack them tight. So you're restricted to certain brands. Duracell and Energiser are available worldwide, some other brands like GP and Varta are common in a few areas.
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